The present invention relates to embodiments of a system, controller and method for preventing vehicle rollaway on a commercial vehicle equipped with an air brake system. Vehicle rollaway may occur during the time period when the vehicle is transitioning from a service brake application by the driver to a parking brake application. Commercial vehicles equipped with air brake systems may begin to roll during the transition time from the initiation of a parking brake application until the parking brakes are fully engaged if the driver removes or reduces the service brake application during the transition time. Rollaway is more pronounced if the vehicle is on a grade and/or carrying a heavy load. Preventing vehicle rollaway is desirable.